A deduplication function is an important characteristic in a storage system. After the deduplication function is introduced into the storage system, storage of duplicate data can be reduced, and storage space is therefore saved.
In the prior art, a deduplication operation generally includes the following process:
A fingerprint of a data block is obtained; a fingerprint table is queried to determine whether the fingerprint table includes the same fingerprint; if the fingerprint table does not include the fingerprint, a storage address is allocated in a storage area, and the data block is stored at the storage address; and a mapping relationship between the fingerprint and the storage address and a mapping relationship between a logical block address of the data block and the fingerprint are established in the fingerprint table. When a data block with the same fingerprint is repeatedly written, only a mapping relationship between a logical block address of the repeatedly written data block and the fingerprint needs to be established, and there is no need to store the repeatedly written data block again. By using a deduplication technology in the prior art, storage space is saved; however, there is a problem of a large amount of data in a fingerprint table.